Stabilize Cliff and Repair Erosion at Hillside - Vandegrift and Rattlesnake Canyon
Owner: NAVFAC Southwest (SYSCOM), USMC
Location: MCB Camp Pendleton, Oceanside, California
Designer: Harris and Associates / GSI
Contractor: Orion Construction Corporation
Delivery Model: Design-Build
Contract Value: $4.6 million
Schedule: 2021 – 2022
Scope:
PE2089M – Stabilize Cliff at Rattlesnake Canyon Rd and Vandegrift Boulevard (Slopes 1-4)
Slopes 1 and 2 had a concrete swale system installed to manage runoff and reduce ponding at the top. A four-foot-wide swath was graded from the back of the existing AC dike, and the area was cleared as needed. Utilities were relocated for the grading and installation of the K Rail rockfall barricade system, which was installed along the back of the existing AC dike using 20-foot rails and 10-foot rails where road curvature caused separation. Slope 3 was too steep and too close to the road to allow installation of the K Rail barricade system, so a wire-mesh/cable-net slope protection system was installed over the face of the slope. Slope 4 comprises two distinct areas: Area 1, approximately 280 linear feet near the intersection of Vandegrift Boulevard and 11th Street, and Area 2, about 160 linear feet located 150 feet east along Vandegrift Boulevard. The repair method involved grading overhanging soil to a 1:2 slope and pruning tree roots over ½” in diameter along the slope face and removing any trees and their stumps within 10 feet of the slope top. Lastly, a 4-foot area was graded with a K rail installed on the back of the sidewalk.
PE2238M – Repair Erosion Damage at Hillside at Vandegrift Boulevard (Slopes 5-11)
Slopes 5-11 were too steep, and erosion was causing debris to slip onto Rattlesnake Canyon Road. The faces of the slopes were graded from the existing toe of slope at a 1:2 slope until daylighted at the top of the slope.
Challenges: The project required extreme safety measures due to its location on major thoroughfares and the work being performed on sheer cliff faces that were highly unstable. Daily safety briefings were held to identify the day's work plans and the hazards to be aware of.
Results: This project increased the safety for motor vehicles, pedestrians, and bicyclists along Vandergrift Blvd and Rattlesnake Canyon Road, providing a safe route for installation residents on two of the major thoroughfares on Cam Pendleton.
